Trammel.



I3. A'. NELSON.

TRAMMEI..

APPLICATION FILED IuLY I5. 1916.

Patented Mar. 13, 1917.

UNITED sTaTEs PATENT OFFICE.

ROBERT ALDEEN NELSON, OEOAKLAND, oALrEoENrn.

TRAMMEL.

Application led July 15, 1916.4

To all 'whom t mag/ -00n0em: v.

Be it known that -I, ROBERT A. NELSON, a citizen of the United States, and a resident of Oakland, inthe county of Alameda and State of California, have invented a newand Improved Trammel, of which the following is a` full, clear, and exact descrip- Y tion.

My invention relates to a trammel or beam compass.v Objects ofthe invention are to provide a novel means for adjusting the trammel point and for holding it securely in the adjusted'position; to provide improved clamping means to secure the device to a beam; and to provide a novel caliper attachment that may be readily applied to the trammel points.

The invention will be particularly eX- Y plained in the specific description following.

Reference is to be had to the accompanying drawings forming a part of this specification in which similar reference characters indicate corresponding parts in all the views. j

Figure 1 is a side elevation of a beam compass, embodying my invention, one of the trammels being in vertical section;

Fig. 2 is a transverse vertical section on the line 2 2, Fig. 1;

Fig. 3 is a similar section on the line 3-3, Fig. 1. Y

Since both the trammels are alike, it will suilice to refer particularly to one.

The body 10 of the trammel has an oblong opening, as usual, to receive the beam 11. A set screw 12 serves to clamp the trammel to the beam, and in order that the set screw may not mar the beam, a wear plate or follower 13 is provided above the beam, said plate having at the upper side guide studs 13 extending through vertical pinholes 10a in the body 10.

In order to adjust the trammel point 16 and house the adjusting means, as well as to provide for securely fastening the point in adjusted position and enable the adjustments to be effected with facility and despatch, the following means is employed:`

At the lower end of the body 10, a horizontally disposed box-like extension 14 is formed, one end being open. In the said extension, a block 15 is slidably fitted and to said block, at the under side, the trammel 16 is secured so as to move with the block. A longitudinal slot 17 in the under side of the extension 14 and communicating with Specication of Letters Patent.

Patented'ivrai. 13, 1917.

serial No. 109,446.

the interior thereof, permits ofthe sliding.I

movement of thetrammel point in response to the movement of the blockl; The block 15 is moved longitudinally by a. horizontal screw "1S, taking into the' threaded fboreof said block. The screw vertical end wall of the eXtension14 by a collar 19, the arrangement being suchthat` by a' turning of the knurled head of the` point and receives a nut 22 for binding the` trammel point in position, a washer 23 `being preferably provided between the nut 22 and the under side of the extension 14 at the slot 17. Y Y

In practice it will be clear that the loosening of the nut 22 will permit Vthe block 15 f to be moved by the screw 18 to adjust the is. clamped tothe taking into backward or soV position of the trammel` point, and the tightening up of the nut 22 will then serve to firmly hold the point linV the adjusted position. The arrangementvprovides a neat construction and houses the adjustingblock and screw, leaving only the set nut 22 below the extension 14.

To convert the trammel or compass into calipers, an attachment 24 is provided and formed with a tubular shank tapering at the lower end to fit over the'trammel Vpoint 16, said shank being secured Vto the trammel point by a set screw 25 and having its lower end 26 turned laterally.

I-Iaving thus described my invention, I

claim as new and desire to secure byLetters Patent: j.

1. A trammel including a lbody having a transverse vopening to receive a beam and formed with a box-like extension at the lower end below said opening, one end of said extension being open, and there being a longitudinal slot'in the bottom of said eX- tension communicating with .theVV interior thereof, a block slidable longitudinally in said extension and having a threaded bore,

l loo y.

a screw sgviveled'to the Wall of the said extension opposite the open end and provided With Va head at the exterior of said "Wall, said screw engaging the threaded bore of the block, a trammel p-int extending at itsV upper end through the longitudinal slot of said extension and detachably secured to the under side of the said block, said point having a threaded section adjacent to the 'upper end extending through the said slot, a nut on said threaded section, and a Washer between said nutV and the under side of the plate in the opening of the body; to bear extension. Y y

. 2. A trammel including a body 'ormed With a transverse opening to receive beam,

said body having a YVhorizontally disposed@ box extensioni integral With Vsaid body be- 10W the said opening, a block housed wthi *said box extension and slidable lceigitudr nally therein, a screw engaging said block to move the said block back andv forth in said extension, the bottom of said extension n clamp nut threaded onto theY said point ate the under side of said extension. Y

` 3. A Vtrammel having a body formed with a transverse openingjto receive a beam, a trammel point in said body at the lower end,l a set screw inE said body and extending into the opening at the top thereof, Ya clamp against the beam, and guide pins on said @lampi plate extending through members on the body, the said pins having heads above the said body members to limit the down-` ward: movement of the clamp plate and prevent 'displacement of the latter. f

ROBERTQALDEEN NELSON.y

Copies of this :patent may be obtained forfve cents eachp by adressing the v"Gonunissionef of Patents,

Washington, DU. Y er 

